riot act
Noun
Meaning
a former English law requiring mobs to disperse after a magistrate reads the law to them
a vigorous reprimand
Source: WordNetHypernyms
Examples
I read him the riot act
Another paper reminded its readers that Bush had (unjustly) read the riot act to Pakistan, telling Pakistan that its relationship with the US was ‘unequal’.
I thought he was also going to read them the riot act but instead he said good-naturedly, “So you guys staying with me all day or what?”
The state PDP chairman, Chief Charles Babatunde Ezekwem, read the riot act while addressing party stakeholders in Owerri.